Analyses of bovine luteal fractions obtained by FACS reveals enrichment of miR-183-96-182 cluster miRNAs in endothelial cells

Our previous studies showed that the miRNA clusters, miR-183-96-182 and miR-212-132, may be critical in promoting luteal cell survival and progesterone production in both bovine and humans. To further understand their involvement in luteal development, this study aimed to establish the expression of these miRNAs in different bovine luteal cell types, namely, endothelial and steroidogenic, isolated using fluorescence-activated cell sorting (FACS). We isolated each of the two cell populations based on the presence of the endothelia surface marker, CD144, and uptake of the lipophilic dye, Nile Red, respectively. Using quantitative Polymerase Chain Reaction (qPCR) in the sorted cell fractions we confirmed that CD144 and the endothelia-specific miRNA, miR-126, were predominantly expressed in endothelial cells (CD144+), whereas HSD3B1 was expressed predominantly in steroidogenic cells (Nile Red^HI). Finally, we found that whereas the miR-212-132 cluster was expressed at similar levels in luteal endothelial and steroidogenic cells, miR-183-96-182 was expressed at > 4-fold higher levels in endothelial than in steroidogenic cells (P < 0.05), suggesting that these two miRNA clusters, and particularly miR-183-96-182, may be important in functionally regulating not only steroidogenic cells but also endothelial cells in the corpus luteum (CL).